Document feeding equipment is used by post offices and businesses to process mail or other documents at high speeds and in high volumes. In postal applications, a stack of upright envelopes is placed in a feed tray, and the stack is advanced against one or more moveable roller or feeder elements which engage the leading envelope, rapidly remove it from the stack, and transfer it to a processing station. However, the pressure placed on the rollers or feeder elements, and the resulting torque applied to the lead document, is not controlled and is not constant. As a result, more than one document is sometimes removed from the stack at a time, requiring additional apparatus to separate the multiple documents. Further singulation is inefficient, however, and increases the complexity and efficiency of the equipment. Thus, there is a need for document feeding equipment which does not remove more than one document from a stack at a time, and which controls the normal force applied by a magazine to a stack of documents whereby the lead document is removed from the stack upon the application of minimum torque.
Accordingly, one object of this invention is to provide new and improved methods and apparatus for feeding documents.
Another object is to provide new and improved methods and apparatus for individually removing documents from a stack of documents, without removing multiple documents.
Still another object is to provide new and improved methods and apparatus for removing documents from a stack of documents by controlling the normal force applied by a moveable feed element to a stack of documents, whereby a minimum torque is applied to the lead document in the stack to remove the lead document from the stack.